Manufacture of viscose rayon



United States Patent Ofiice MANUFACIURE F VISCOSERAYON Ne Drawing. Filed June 6, 1958, Ser. No. 740,188 1 Claims. 01. 18-54) The present invention relates to the manufacture of rayon yarns, filaments, films, and the like and more particularly to the manufacture of viscose rayon yarn that is characterized by its high tenacity, high resistance to abra-. sio'n, andlow swelling which makes it especially suitable for use reinforcing rubber articles such as conveyor belts and tires where yarn having a tenacity of about 500 g./ 100 den. is required.

Improvements in the physical properties of rayon have been and are being made. The most important recent development leading to such improvements is the use of special additives in the spinning system. The precise theory of how the additives affect the coagulation and regeneration of cellulose in the jviscose solution to produce an improved yarn has not been definitely established, with various and different views having been expressed.

However, it is known that these additives, now referred t maintain the :acid content in, the regenerating andtcoagu lating bath within strict limits, if yarn having improved properties is produced.

When alkoxylated amines are used alone as viscose modifiers, it is necessary to keep the acid content of the primary bath within very strict limits and to adjust the acid content very accurately to correspond with the alkali chutentlof viscose with the result that the acid concentratiou has to be kept very low. Such low acid concentrations cause spinning 'difiiculties to occur. The use of polyglycols as viscose modifiers results in less difiiculty during spinning because an acid range having wider limits may be employed; however, the strength of yarns pror 1 duced under the influence of polyglycols alone are not entirely satisfactory. Therefore, the processes of producing yarn havingimproved strength, low swelling, and high abrasion resistance in the presence of known modifiers have many drawbacks and give rise to many operational 1 l 0 It is an object of the present in'vention'to provide a viscose spinning composition containing a novel combination of modifiers from which viscose rayon yarn of improved physical properties may be produced.

It is another object of the present invention to provide l a .method for the manufacture of viscose rayon yarn ,which has improved physical properties. These and other objects are accomplished in accordance with'the' present invention by. incorporating into vis- I Oose solution a mixture of modifiers comprising an a1koxylated amine and a polyglycol in the amount of 1.0- 5.0 g./ kg. of solution, spinning the resultant viscose solution into an aqueous coagulating and regenerating primary bath which contains sulfuric acid, sodium sulfate, and zinc sulfate in the amountofat least 30 g./kg. of bath to form viscose rayon yarn, withdrawing the yarn from the primary bath, and passing the yarn through a hot second bath wherein the yarn is given a substantial stretch.

It has been found that best results are obtained when the mixture of modifiers contains 15-50% polyglycol and correspondingly -50% alkoxylated amine and when the total quantity added is between 1.0-5.0 g./kg. of viscose solution, preferably between 1.2 and 2.5 g./kg.' With the addition of the combination of modifiers in the afore mentioned amounts, the spinning process proceeds satisfactorily, the operable limits of the acid content in the primary bath is wide, and the ability of the freshly spun thread to accept a high stretch is excellent. In general, the amines contemplated for use in the pres ent invention have the following general formula:

In this formula R and R represent alkylene oxide chains of the type, --(C,,H ,,O) H, wherein x and n can bediff ferent fo r R -and R with the sum of the alkylene oxide units being at least 5. R may be selected from the group consisting of hydrogen, an alkylene oxide chain, an alkyl radical, a cyclic radical, a heterooyclic radical and a nitrov gen-containing group of the formula:

in which X may be an aliphatic, aromatic, or alicyclic radical, and R and R may be hydrogens, alkylene oxide chains, or aliphatic, cyclic, or heterocyclic radicals.

The polyglycol is preferably polyethylene glycol. The molecular weight of the polyglycol may vary depending upon the spinning conditions and the particular amine employed.

The primary bath into'which the viscose solution con? taining the mixture of additives is extruded should contain Zinc s ulfatein the amount of at least 30 g./kg. of solution. The sulfuric acid concentration of the bath for better results should be the same as or somewhat lower than the alkali content of the viscose solution. However, the acid content may exceed the alkali content when the cellulose content of the viscose solution is extremely low or when the viscose solution is spun with a relatively high gamma number.

The -rnodifiers may be incorporated in the spinning systern in a variety-of ways, such as by adding them during the dissolving operation, or by injecting them into a stream of viscose being pumped to a spinneret.

The yarn produced in accordance with the present invention has low swelling, increased resistance to abrasion, and increased tenacity. Furthermore, thejyarn has the so-called skin structure and non-crenulated surfaces normally associated with yarn produced under the influence of a viscose modifier.

The following examplesare illustrative of thepresent invention; all concentrations unless otherwise noted are calculated as percentages by weight basedon the viscose solution or the spinbath.

Example 1 cellulose and5.5% alkali-was prepared inthe usual way.

Patented May. 9, 196,1,-

To this viscose solution a mixture of additives composed and 20% of polyethylene glycol having a molecular Weight of 400 was added in the amount of 1.5 g./kg. of viscose solution. The viscose solution was filtered, deaerated, and aged, 'The viscose solution, having a maturity of 46 garnnranumber, a viscosity of 50 seconds as determined by the ball-fall method, and a Hottenroth ripeness of-22 was spun into 1000 filament yarn by extruding s in hm a pinuer t intoa pri a c u ing and regenerating bath containing 4.2% sulfuric acid, 6.0% zinc sulfate, and 13% sodium sulfate. The temperature of the primary bath was maintained at 45 C. The yarn was directed through an elongated spinning tube disposed coaxially with the spinneret and through which the primary bathflowed concurrently with the yarn. After being directed through the primary bath, the yarn was withdrawn therefrom by means of a first godet. Then the yarn was guided into and through a hot aqueous second bath containing 2% sulfuric acid and withdrawn therefrom by means of a' second godet. Due to a predetermined differential in the peripheral speeds of said godets, the yarn was stretched 125% therebetween. The yarn draw oif speed was 40 meters per minute. The yarn was collected on bobbins and washed. Then the yarn was given a final stretch and dried while being passed over a" heated cylindrical drier. The resulting yarn had a denier of 1650. The yarn so produced had an air dry strength of 500 g./ 100 den., wet strength of 350 g./100 den., an air dryv elongation of 9.7%, and a wet elongation of 20.7%. Cord having a construction of 12 x 12 and made from the yarn had an air dry strength of 333 g./100 den. and an oven dry strength of 400 g. /100 den.

For comparison purposes, yarn was produced under the above conditions except that the sole additive employed was the ethoxylated amine. The yarn so produced had an air dry strength of 462 g./100 den., a wet strength of 317 g./100 den., an air dry elongation of 9.7%, and a wet elongation of 20.7%. 'Cord manufactured from the yarn had an air dry strength of 300 g./100 den. and an oven dry strength of 355 g./100 den.

Yarn was also produced under the above conditions except that the sole additive was polyethylene glycol with a molecular weight of 1500. In order to produce yarn having the :best possible physical properties, it was necessary to increase the acid content in the primary bath to 5.2%. The yarn so produced had an air dry strength of 484 g./100 den., a wet strength of 348 g./100 den., an air elongation of 12.3%, and a Wet elongation of 23.3%. Cord manufactured from the yarn had an air dry strength of298 g./100 den. and an oven dry strength of 370 g./100 den.

Example 11 A viscose solution having the composition of 7.3% cellulose and 5.5% alkali was prepared in the usual way. To this viscose solution a mixture of additives composed of 83% of the amine described in Example I and 17% of polyethylene glycol having a molecular weight of 1500 was added in the amount of 2.0 g./kg. of viscose solution. Spinning was carried out in the same manner as in Example I. The yarn so produced had an air dry strength of 497 g./100 den., a wet strength of 382 g./100 den., an air dry elongation of 11.6%, and a wet elongation of 24.9%. Cord manufactured from the yarn had an air dry strength of 328 g./100 den. and an oven dry strength of 400 gl/ 100 den.

Example III A is e 911 40 hav n e c mposi o of pllulo e M151 .5 Z a ta if was g eps jg n he usual W 2,983,572 I r V To this viscose solution a mixture of additives composed of 70% of the alkoxylated amine having the formula:

and 30% of a 2:1 mixture of polyethylene glycols having respective molecular weights of 400a'nd 1500 was added in the amount of 1.8 g./kg. of viscose solution. Spinning was carried out in the samemanner as inExample 1, except that the primary bath in this instance contained 4.6% sulfuric acid, 5.0% zinc sulfate, and 13% sodium sulfate. The yarn so produced had an air dry strength of 509 g./ den., a wet strength of 388 g./10o den., an air dry elongation of 11.6%, and a wet elongation of 25.3%. Cord manufactured from the yarn had an air dry strength of 338 g./100 den. and an oven dry strength of 412 g./100 den.

Example IV A viscose solution having the composition of 6 .5% cellulose and 5 .5 alkali was prepared in the usual way. To this viscose solution a mixture of additives composed of 55% of the ethoxylated amine having the formula! and 45% of polyethylene glycol having a molecular weight of 400 was added in the amount of 1.4 gJkg. of viscose solution. Spinningwas carried out in the same manner as in Example 1, except that the primary bath in this instance was maintained at 48 C. and contained 5.2% sulfuric acid, 5.0% zinc sulfate and 14% sodium sulfate, and that the second bath contained 2.5% sulfuric acid. The yarn so produced had an air dry strength of 520 g./100 den., a wet strength of 375 y g./ 100 den., an air dry elongation of 11.0%, and a wet elongation of 24.5%. Cord manufactured from the yarn had an air dry strength of 350 g./ 100 den. and an oven strength of 412 g./100 den.

Example V A viscose solution having the composition of 7.3%. cellulose and 5.5% alkali was prepared in the usual way. To this viscose solution a mixture of additives composed of 75% of the ethoxylated amine compound having'the formula:

and 25% of polyethylene glycol having a molecular weight of 1500 was added in the amount of 2.0 g./kg. of viscose solution. The viscose solution was spun at a gamma number of 46, a viscosity of 55 seconds asv determined by the ball-fall method, and a Hottenroth ripeness of 20 into a primary coagulating and regenerating bath. The bath contained 4.7% sulftuic acid, 3.5% zinc sulfate and 14% sodium sulfate and was maintained at a temperature of 45 C. Stretching in a second hot bath and aftertreating the yarn was effected in a manner identical to that employed in Example I. The yarn so produced had an air dry strength of 488 g./100 den., a wet strength of 360 g./100 den., a dry elongation of 11.2%, and an air elongation of 24.3%. Cord manufactured from the yarn had an air dry strength of 331 g./100 den. and an oven dry strength of 405 g./100 den.

Example VI A viscose solution having the composition of cellulose and 5.5% alkali was repared the usual way. To this viscose solution a mixture of additives CzHaOhH the ball-fall method, and a Hottenroth ripeness of 19 into a primary coagulating and regenerating bath. The bath contained 5.1% sulfuric acid, 6.0% zinc sulfate, and 12.5% sodium sulfate and was maintained at a temperature of 48 C. After being formed in the primary bath, the yarn was withdrawn therefrom and stretched 120% in a second bath containing 2% sulfuric acid and maintained at a temperature of 90 C. The yarn was 'aftertreated in the usual way. The yarn so produced had an air dry strength of 495 g./100 den., a wet strength of 375 g./ 100 den., an air dry elongation of 11.0% and a wet elongation of 24.5%. Cord manufactured from the yarn had an air dry strength of 334 g./100 den. and an oven dry strength of 408 g./100 den.

While preferred embodiments of the invention have been shown, it is to be understood that changes and variations may be made without departing from the spirit and scope of the invention so defined by the appended claims.

What is claimed is:

1. A method of producing viscose rayon yarn having improved physical properties comprising spinning a viscose solution containing a mixture composed of 85-50% ethoxylated amine and -50% of polyethylene glycol in the amount of 1.0-5.0 g./kg. of solution into a coagulating and regenerating bath containing 4.2%-5.2% by weight of sulfuric acid, sodium sulfate, and zinc sulfate in the amount of at least 30 -g./kg. of bath, said ethoxylated amine having the following formula:

wherein R and R represent ethylene oxide chains in.

which the sum of the ethylene oxide units is at least 5, R is selected from the group consisting of hydrogen, an ethylene oxide chain, an alkyl radical, a cyclic radical, a hetcrocyclic radical, and a radical of the formula:

R4 -X-N Rs wherein X is selected from the group consisting of an aliphatic radical, an aromatic radical, and an alicyclic radical, and R and R are selected from the group consisting of hydrogen, an ethylene oxide chain, an aliphatic radical, a cyclic radical, and a heterocyclic radical.

2. The method as defined in claim 1 wherein the mixture is present in the viscose solution in the amount of 1.2-2.5 g./kg. of solution.

3. A method of producing viscose rayon yarn having improved physical properties comprising adding to a viscose solution a mixture composed of 85-50% of the ethoxylated amine having the formula:

and 15-50% of polyethylene glycol in the amount of 1.2-2.5 g./kg. of solution, spinning the resultant solution into yarn in a coagulating and regenerating bath containing 4.2%-5.2% by weight of sulfuric acid, sodium sulfate, and zinc sulfate in the amount of at least 30 gJkg.

of bath, and subjecting the thus-formed yarn to a substantial stretch in a hot secondbath.

4.. A method of producing viscose rayon yarn having improvedphysica'l properties comprising adding 'to' a viscose'solution am-ixture composedof -50%' of the ethoxylated amine having the formula:

A Q oinionn CHa(OHa)uN i aHo hH and 15-50% of polyethylene glycol in the amount of 1.2-2.5 g./kg. of solution, spinning the resultant solution into yarn in a coagulating and regenerating bath containing 4.2%-5.2% by weight of sulfuric acid, sodium sulfate, and zinc sulfate in the amount of at least 30 g./kg.

of bath, and subjecting the thus-formed yarn to a substantial stretch in a hot second bath.

5. A method of producing viscose rayon yarn having improved physical properties comprising adding to a viscose solution a mixture composed of 85-50% of the ethoxylated amine having the formula:

CIHA MH CH:(CHi)u-N caHims and 15-50% of polyethylene glycol in the amount of 1.2-2.5 g./kg. of solution, spinning the resultant solution into yarn in a coagulating and regenerating bath containing 4.2%-5.2% by weight of sulfuric acid, sodium sulfate, and zinc sulfate in the amount of at least 30 g./kg. of bath, and subjecting the thus-formed yarn to a substantial stretch in a hot second bath.

6. A method of producing viscose rayon yarn having improved physical properties comprising adding to a viscose solution a mixture composed of 85-50% of the ethoxylated amine having the formula:

and 15-50% of polyethylene glycol in the amount of 1.2-2.5 gJkg. of solution, spinning the resulting solution into yarn in a coagulating and regenerating bath containing 4.2%-5.2% by weight of sulfuric acid, sodium sulfate, and zinc sulfate in the amount of at least 30 g./kg. of bath, and subjecting the thus-formed yarn to a substantial stretch in a hot second bath.

References Cited in the file of this patent UNITED STATES PATENTS 2,077,412 Herzog Apr. 20, 1937 2,284,028 Ubbelohde May 26, 1942 2,506,249 Tammen May 2, 1950 2,516,316 Hare July 25, 1950 2,648,611 Richter Aug. 11, 1953 2,663,704 Yehling Dec. 22, 1953 (Other references on following page) 7 UNITED STATES PATENTS Diem-R11 2; Dec. 7, 1954 Oha fles 'et a1. June" 14', 1955 Bun-095s Dc. 4, 1956 Edwards et a1. Jan. 15, 1951 Sti1de'1 Q.... June 18', 1957 Mitbhell 86151.3, 1957 Lytton July 1, 1958 8 Ly tton et a1. July 29, 1958 Lytton Aug. 26, 1958 Cox et a1 Sept. 16,1958- Hollihon et a1 Sept. 16, 1958 Locher Apr. 28, 1959 Howsmon June 30, 1959 FOREIGN PATENTS Great Britain May 2, 1951 Great Britain Dec. 14, 1955 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N0. 2,9835 72 May 9 1961 Hugo Elling et a1.

t error appears in the above numbered pat- It is hereby certified the Patent should read as ent requiring correction and that the said Letters corrected below In the heading to the print d .s ecifi I cat 0 lines 7 and 8 ins ert the fOllOWiIlg: p l between Claims priority application Germany June 21,, 1957 (SEAL) Attest:

ERNEST W. SWIDER Attesting Officer DAVID L. LADPD Commissioner of Patents USCOMM-DC- 

1. A METHOD OF PRODUCING VISCOSE RAYON YARN HAVING IMPROVED PHYSICAL PROPERTIES COMPRISING SPINNING A VISCOSE SOLUTION CONTAINING A MIXTURE COMPOSED OF 85-50% ETHOXYLATED AMINE AND 15-50% OF POLYETHYLENE GLYCOL IN THE AMOUNT OF 1.0-5.0 G./KG. OF SOLUTION INTO A COAGULATING AND REGENERATING BATH CONTAINING 4.2%-5.2% BY WEIGHT OF SULFURIC ACID, SODIUM SULFATE, AND ZINC SULFATE IN THE AMOUNT OF AT LEAST 30 G./KG. OF BATH, SAID ETHOXYLATED AMINE HAVING THE FOLLOWING FORMULA: 